Please help me decipher this

Since English is my second language, I sometimes have a problem understanding what people say. That being said, I'm looking to buy a cheap Chinese split focusing screen for my K10. I've read this question from a previous buyer wrote to the seller and I have a hard time trying to figure out what the heck he meant. Here's the original question:

"Hi I'm very interested in this item, but I prefer a Horizontal Screen. It says you do that by request. How would I go about getting that done? Also, is it possible to have that tab that is on the original screen to help replace it? Would making it horizontal degrade the quality in any way? Sorry for all the questions. thanks"

Can someone help explain to me what "that tab that is on the original screen" this buyer referred to and exactly what does he wants to do with it? Thank you in advance.